The case, which was led by investment banker Gina Miller,
rejected the government's argument that it could use the legal
mechanism of royal prerogative to allow May to trigger Article 50
without receiving the consent of parliament first.

But confusion still remains over the finer legal details of
Article 50 once it has actually been triggered, which Theresa May
says will happen by March 2017.

On the other hand, if Article 50 cannot be reversed, then
Brussels would have far more bargaining power in negotiations, as
Britain would face accepting whatever terms it was offered or
leaving the EU without a deal, knowing that it only had two years
to complete the exit process.

"Government lawyers also made clear in legal proceedings before
the High Court that, as a matter of firm policy, notification of
withdrawal will not be withdrawn."

The government has now announced that it will challenge the High
Court's decision to make the government consult parliament before
triggering Article 50, meaning that an appeal will be heard in
the UK Supreme Court.